2019 Tesla Model 3 - Which charge level?

What setting does it come with from Tesla? Any evidence that’s incorrect?

That’s like asking how much sugar your coffee comes with. It’s the user’s choice. There is no one “correct” amount of sugar in coffee.

The charge levels are “correct” or not based on the mission of the day. If you’re going on a long road trip, a lower charge isn’t appropriate. If you’re just going to the store and back, the highest charge level is unnecessary.

Put another way, if you buy a normal car from a dealership, and they deliver it with only half a tank of gas, that isn’t evidence that you shouldn’t ever fill it all the way up.

OK, let’s try again - how much does it charge if you plug it in and leave it, as Tesla instructs? If it was better to halt charging at, say, 80%, wouldn’t Tesla have set it up that way?

Trying again: Tesla suggests to plug it in and leave it at all charging level settings. The vehicle will charge up to the level that you specify, and then trickle-charge to maintain that level.

The “plug it in and leave it” instruction is to assuage concerns from people who remember the days when you had to take cell phones off of the charger after they were fully charged lest you shorten the battery life, which was very inconvenient if you charged at night because no one wanted to wake up at 2am to unplug the phone.

It is sometimes better to charge to 80%, and sometimes better to charge to 100%, and sometimes better to charge to 60%. It depends entirely on the individual mission, so there is no one “default” charge state any more than there is a factory-recommended radio volume. It’s entirely up to the user, and the user has to do their own figuring as to the pros and cons of choosing different settings.

“Fueling” electric cars is probably better thought of in terms of fueling airplanes. Whereas most people fill the tank when they gas up a car, doing that routinely in an airplane is a good way to waste money and lower your passenger/cargo capacity unnecessarily. So pilots choose a fuel level for a trip based on how far they’re flying, and what they’re carrying.

If they only need to go 60 miles, then fueling it for 1,600 miles would be silly because now you have to carry all that extra fuel around, and that adds weight which means you have to fly at lower altitudes/higher power settings, and it also reduces capacity because airplanes are only rated to a maximum gross weight, and full fuel + full passenger/cargo load on many airplanes would be over that max weight.

There is no “default” fuel level in an airplane, and the “factory recommended settings” are essentially “enough fuel to not run out before you land.”

That’s a good way to consider charge levels in EV’s too. Charge it enough to not run out of electricity before your next charging opportunity. If you live 10 miles from your office, then don’t charge it to 100% for your daily commute because that puts unnecessary strain on the battery and will reduce its longevity for no reason. If you’re going camping 5 hours away, then charge it all the way to full because the mission calls for it.

Doesn’t it come from the factory with a default charging level setting?

What “pro” is there to less than 100%?

And you know this how, with respect to Tesla’s charging system?

Because I know how lithium-ion batteries work (admittedly, I cheat – we use Li-ions in a lot of our equipment at my office).


Li-ion does not need to be fully charged as is the case with lead acid, nor is it desirable to do so. In fact, it is better not to fully charge because a high voltage stresses the battery. Choosing a lower voltage threshold or eliminating the saturation charge altogether, prolongs battery life but this reduces the runtime. Chargers for consumer products go for maximum capacity and cannot be adjusted; extended service life is perceived less important.

So Tesla doesn’t know about the batteries it makes in its plant and puts in its cars? Tesla buyers need to guess for themselves about how to charge their cars?

From my previous post.

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Not a matter of guessing.
Tesla, like any other company, makes compromises in their designs.
The user however can make choices to optimize for their situation.
Like changing transmission fluid even though the maker says “lifetime” use is OK.

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That’s a generic battery care site, more suitable for laptops and phones being charged by a $30 power supply. My point is that Tesla has specific advice on how to charge their batteries, using their equipment and governed by their sophisticated charging software. Nobody has provided any evidence that they have a better way to take care of a Tesla.

Yes they have - you’re just dismissing all of it. There’s nothing magic about the Tesla Li-ion batteries that make them behave differently from other Li-ion batteries from a longevity standpoint.

But here, from Tesla:

What percentage should I charge the battery to?
Adjust how full the battery charges from the charge settings menu. For regular use, we recommend keeping your car set within the ‘Daily’ range bracket, up to approximately 90%. Charging up to 100% is best saved for when you are preparing for a longer trip.

So there’s the answer, from Tesla. Why is anyone wondering?

And what is the ‘default’ setting on a Tesla, as delivered?

Did you miss this quote from Circuitsmith? That’s why people are wondering. Because sometimes manufacturers tell you to do things that sound good from a convenience perspective but aren’t as good for the longevity of the car.